On Wed, Jun 06, 2018 at 03:42:08PM +0200, Daniel Lezcano wrote: > On 06/06/2018 14:23, Peter Zijlstra wrote: > > On Tue, Jun 05, 2018 at 11:16:40AM +0200, Daniel Lezcano wrote: > >> + atomic_t idle_duration_ms; > >> + atomic_t run_duration_ms; > > > >> + idle_duration_ms = atomic_read(&ii_dev->idle_duration_ms); > > > >> + run_duration_ms = atomic_read(&ii_dev->run_duration_ms); > > > >> + atomic_set(&ii_dev->run_duration_ms, run_duration_ms); > >> + atomic_set(&ii_dev->idle_duration_ms, idle_duration_ms); > > > >> + *run_duration_ms = atomic_read(&ii_dev->run_duration_ms); > >> + *idle_duration_ms = atomic_read(&ii_dev->idle_duration_ms); > > > >> + if (!atomic_read(&ii_dev->idle_duration_ms)) > > > >> + if (!atomic_read(&ii_dev->run_duration_ms)) > > > > What is the point of atomic_t here ?! > > idle_duration and run_duration can be changed from different places at > the same time. The atomic is here to ensure the read/write are consistent. > > Do you think it is pointless ?
Yes, atomic_read() / atomic_set() are no more atomic than READ_ONCE() / WRITE_ONCE().
